Sugar hydrolysates can be used for microbial production of a variety of fine chemicals or biopolymers, such as organic acids e.g. lactic acid, or ethanol or other alcohols e.g. n-butanol, 1,3-propanediol, or polyhydroxyalkanoates (PHAs). The sugar hydrolysates may also serve as raw material for other non-microbial processes, e.g., for enrichment, isolation and purification of high value sugars or various polymerization processes. One of the major uses of the sugar hydrolysates is in the production of biofuels. The production of bioethanol and/or other chemicals may take place in an integrated process in a biorefinery (Wyman 2001).
Limited resources of fossil fuels, and increasing amounts of CO2 released from them and causing the greenhouse phenomenon have raised a need for using biomass as a renewable and clean source of energy. One promising, alternative technology is the production of biofuels i.e. ethanol from cellulosic materials. In the transportation sector biofuels are for the time being the only option, which could reduce the CO2 emissions by an order of magnitude. The ethanol can be used in existing vehicles and distribution systems and thus it does not require expensive infrastructure investments. Sugars derived from lignocellulosic renewable raw materials can also be used as raw materials for a variety of chemical products that can replace oil-based chemicals.
Most of the carbohydrates in plants are in the form of lignocellulose, which essentially consists of cellulose, hemicellulose, pectin and lignin. In a lignocellulose-to-ethanol process the lignocellulosic material is first pretreated either chemically or physically to make the cellulose fraction more accessible to hydrolysis. The cellulose fraction is then hydrolysed to obtain sugars that can be fermented by yeast into ethanol. Lignin is obtained as a main co-product that may be used as a solid fuel.
Bioethanol production costs are high and the energy output is low, and there is continuous research for making the process more economical. Enzymatic hydrolysis is considered the most promising technology for converting cellulosic biomass into fermentable sugars. However, enzymatic hydrolysis is used only to a limited amount at industrial scale, and especially when using strongly lignified material such as wood or agricultural waste the technology is not satisfactory. The cost of the enzymatic step is one of the major economical factors of the process. Efforts have been made to improve the efficiency of the enzymatic hydrolysis of the cellulosic material (Badger 2002).
US 2002/019 2774 A1 describes a continuous process for converting solid lignocellulosic biomass into combustible fuel products. After pretreatment by wet oxidation or steam explosion the biomass is partially separated into cellulose, hemicellulose and lignin, and is then subjected to partial hydrolysis using one or more carbohydrase enzymes (EC 3.2). Celluclast™, a commercial product by Novo Nordisk A/S containing cellulase and xylanase activities is given as an example.
US 2004/000 5674 A1 describes novel enzyme mixtures that can be used directly on lignocellulose substrate, whereby toxic waste products formed during pretreatment processes may be avoided, and energy may be saved. The synergistic enzyme mixture contains a cellulase and an auxiliary enzyme such as cellulase, xylanase, ligninase, amylase, protease, lipidase or glucuronidase, or any combination thereof. Cellulase in considered to include endoglucanase (EG), beta-glucosidase (BG) and cellobiohydrolase (CBH). The examples illustrate the use of a mixture of Trichoderma xylanase and cellulase preparations.
Kurabi et al. (2005) have investigated enzymatic hydrolysis of steam-exploded and ethanol organosolv-pretreated Douglas-fir by novel and commercial fungal cellulases. They tested two commercial Trichoderna reesei cellulase preparations, and two novel preparations produced by mutant strains of Trichoderma sp. and Penicillium sp. The Trichoderma sp. preparation showed significantly better performance than the other preparations. The better performance was believed to be at least partly due to a significantly higher beta-glucosidase activity, which relieves product inhibition of cellobiohydrolase and endoglucanase.
US 2004/005 3373 A1 pertains a method of converting cellulose to glucose by treating a pretreated lignocellulosic substrate with an enzyme mixture comprising cellulase and a modified cellobiohydrolase I (CBHI). The CBHI has been modified by inactivating its cellulose binding domain (CBD). Advantages of CBHI modification are e.g. better recovery and higher hydrolysis rate with high substrate concentration. The cellulase is selected from the group consisting of EG, CBH and BG. The CBHI is preferably obtained from Trichoderma. 
US 2005/016 4355 A1 describes a method for degrading lignocellulosic material with one or more cellulolytic enzymes in the presence of at least one surfactant. Additional enzymes such as hemicellulases, esterase, peroxidase, protease, laccase or mixture thereof may also be used. The presence of surfactant increases the degradation of lignocellulosic material compared to the absence of surfactant. The cellulolytic enzymes may be any enzyme involved in the degradation of lignocellulose including CBH, EG, and BG.
There is a huge number of publications disclosing various cellulases and hemicellulases.
Cellobiohydrolases (CBHs) are disclosed e.g. in WO 03/000 941, which relates to CBHI enzymes obtained from various fungi. No physiological properties of the enzymes are provided, nor any examples of their uses. Hong et al. (2003b) characterizes CBHI of Thermoascus aurantiacus produced in yeast. Applications of the enzyme are not described. Tuohy et al. (2002) describe three forms of cellobiohydrolases from Talaromyces emersonii. 
Endoglucanases of the cel5 family (EGs fam 5) are described e.g. in WO 03/062 409, which relates to compositions comprising at least two thermostable enzymes for use in feed applications. Hong et al. (2003a) describe production of thermostable endo-β-1,4-glucanase from T. aurantiacus in yeast. No applications are explained. WO 01/70998 relates to β-glucanases from Talaromyces. They also describe β-glucanases from Talaromyces emersonii. Food, feed, beverage, brewing, and detergent applications are discussed. Lignocellulose hydrolysis is not mentioned. WO 98/06 858 describes beta-1,4-endoglucanase from Aspergillus niger and discusses feed and food applications of the enzyme. WO 97/13853 describes methods for screening DNA fragments encoding enzymes in cDNA libraries. The cDNA library is of yeast or fungal origin, preferably from Aspergillus. The enzyme is preferably a cellulase. Van Petegem et al. (2002) describe the 3D-structure of an endoglucanase of the cel5 family from Thermoascus aurantiacus. Parry et al. (2002) describe the mode of action of an endoglucanase of the cel5 family from Thermoascus aurantiacus. 
Endoglucanases of the cel7 family (EGs fam 7) are disclosed e.g. in U.S. Pat. No. 5,912,157, which pertains Myceliphthora endoglucanase and its homologues and applications thereof in detergent, textile, and pulp. U.S. Pat. No. 6,071,735 describes cellulases exhibiting high endoglucanase activity in alkaline conditions. Uses as detergent, in pulp and paper, and textile applications are discussed. Bioethanol is not mentioned. U.S. Pat. No. 5,763,254 discloses enzymes degrading cellulose/hemicellulose and having conserved amino acid residues in CBD.
Endoglucanases of the cel45 family (EGs fam 45) are described e.g. in U.S. Pat. No. 6,001,639, which relates to enzymes having endoglucanase activity and having two conserved amino acid sequences. Uses in textile, detergent, and pulp and paper applications are generally discussed and treating of lignocellulosic material is mentioned but no examples are given. WO 2004/053039 is directed to detergent applications of endoglucanases. U.S. Pat. No. 5,958,082 discloses the use of endoglucanase, especially from Thielavia terrestris in textile application. EP 0495258 relates to detergent compositions containing Humicola cellulase. U.S. Pat. No. 5,948,672 describes a cellulase preparation containing endoglucanase, especially from Humicola and its use in textile and pulp applications. Lignocellulose hydrolysis is not mentioned.
A small amount of beta-glucosidase (BG) enhances hydrolysis of biomass to glucose by hydrolyzing cellobiose produced by cellobiohydrolases. Cellobiose conversion to glucose is usually the major rate-limiting step. Beta-glucosidases are disclosed e.g. in US 2005/021 4920, which relates to BG from Aspergillus fumigatus. The enzyme has been produced in Aspergillus oryzae and Trichoderma reesei. Use of the enzyme in degradation of biomass or detergent applications is generally discussed but not exemplified. WO02/095 014 describes an Aspergillus oryzae enzyme having cellobiase activity. Use in the production of ethanol from biomass is generally discussed but not exemplified. WO2005/074656 discloses polypeptides having cellulolytic enhancing activity derived e.g. from T. aurantiacus; A. fumigatus; T. terrestris and T. aurantiacus. WO02/26979 discloses enzymatic processing of plant material. U.S. Pat. No. 6,022,725 describes cloning and amplification of the beta-glucosidase gene of Trichoderma reesei, and U.S. Pat. No. 6,103,464 describes a method for detecting DNA encoding a beta-glucosidase from a filamentous fungus. No application examples are given.
Xylanases are described e.g. in FR2786784, which relates to a heat-stable xylanase, useful e.g. in treating animal feed and in bread making. The enzyme is derived from a thermophilic fungus, particularly of the genus Thermoascus. 
U.S. Pat. No. 6,197,564 describes enzymes having xylanase activity, and obtained from Aspergillus aculeatus. Their application in baking is exemplified. WO 02/24926 relates to Talaromyces xylanases. Feed and baking examples are given. WO01/42433 discloses thermostable xylanase from Talaromyces emersonii for use in food and feed applications.
The best-investigated and most widely applied cellulolytic enzymes of fungal origin have been derived from Trichoderma reesei (the anamorph of Hypocrea jecorina). Consequently also most of the commercially available fungal cellulases are derived from Trichoderma reesei. However, the majority of cellulases from less known fungi have not been applied in processes of practical importance such as in degrading cellulosic material, including lignocellulose.
There is a continuous need for new methods of degrading cellulosic substrates, in particular lignocellulosic substrates, and for new enzymes and enzyme mixtures, which enhance the efficiency of the degradation. There is also a need for processes and enzymes, which work at high temperatures, thus enabling the use of high biomass consistency and leading to high sugar and ethanol concentrations. This approach may lead to significant saving in energy and investments costs. The high temperature also decreases the risk of contamination during hydrolysis. The present invention aims to meet at least part of these needs.